According to a related art, a projector is known in which radiated light from a light source is modulated and projected onto a projection surface and in which the amount of light incident on a light valve for modulating light is changed according to the image to be projected in order to expand the dynamic range and thus project an image of higher image quality (for example, JP-A-2004-362820). In the configuration described in JP-A-2004-362820, a movable light shielding plate is arranged in front of the light source, as alight adjustment device which regulates the amount of light, and shuts of part of radiated light, thus enabling the regulation of the amount of light. However, if the light-adjusted state continues for long, the light shielding plate may become overheated by absorption and scattering of light. As a preventive measure, for example, a cooling device for cooling the light shielding plate is provided in the configuration of JP-A-2004-362820.
However, it is conceivable that the cooling by the cooling device may become insufficient, such as in the case where the light source has a high output or in the case where the light adjustment device and the light source are close to each. Therefore, a high cooling capability needs to be secured. Moreover, there also is a problem that the cooling capability needs to be controlled according to the temperature of the light adjustment device, thus complicating the control.